I have a 99 Chrysler 300M. The fuse for the cigarette lighter blew out randomly, so we replaced it. I tested it afterwards and it worked. A few days later I went back out to use it and the fuse was blown again.

There is an obvious short somewhere, but how can I find and fix this problem?

UPDATE: I went to try to replace the fuse once more, but this time it didn't work. I checked the manual and it said the cavity (number 6) was the power outlet. There is a 6A and 6B, however. Under the 6A cavity is says IGN and under 6B is says battery. When I got the car it was under 6A and that's what we have been using, but now it didn't appear to work with even a new fuse. I instead put the fuse in cavity 6B and it worked. I just did this so we'll see how if it blows the fuse again, but I'm hoping this solved the problem. I'll update in a few days or if the fuse blows again.

UPDATE 2: Well that didn't last long. Fuse blew again. I'll have to wait until a nice day again to try the other suggestions people had and update then.

That's interesting - presumably the 'IGN' feed is only active when the ignition switch is on, and the 'battery' feed is active all the time - so you get the choice as to whether your lighter socket is always on or only on with ignition? I've not seen that before...
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Nick CFeb 13 '13 at 15:11

Ford's cig. lighters used to be battery powered. Which is annoying since most devices will drain your battery. Now they are accessory powered, at least on my 2012 Focus. I find it hard to believe Chrysler went a step ahead and gave the user the option. But if so, that's cool.
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NickFeb 15 '13 at 14:21

Since I'm using the battery option, it won't still drain my battery, right? I don't leave anything plugged in after the car is off.
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TannerFeb 15 '13 at 17:53

2 Answers
2

I would just add a comment but I don't have enough points I guess. I just wanted to say you are addressing it correctly. The wrong thing to do (but tempting) is to just throw a bigger fuse in there. Avoid that temptation.

It's possible that someone (previous owner maybe) has tapped into that circuit since it's an easily available 12V source. Trace the circuit from the fuse panel all the way to the lighter.

Do you have a multimeter? Check the current across the fuse (should be zero with nothing plugged in), continuity from fuse-lighter and lighter-ground, and that there isn't any continuity across the lighter.

If you can get to it, unplug the connector from the back of the lighter socket, that way you can check the socket itself separately from the wiring.

No, according to the manual it is just the Power Outlet. However, there are two cavities under the same number for this: one saying IGN and another saying battery. (See updated post for more information)
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TannerFeb 12 '13 at 23:00

You'd have to remove the fuse to get an accurate reading of current.
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NickFeb 15 '13 at 14:24